1 /* 2 * (C) Copyright 2001, 2002 3 * Wolfgang Denk, DENX Software Engineering, wd@denx.de. 4 * 5 * See file CREDITS for list of people who contributed to this 6 * project. 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU General Public License as 10 * published by the Free Software Foundation; either version 2 of 11 * the License, or (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 21 * MA 02111-1307 USA 22 * 23 * This has been changed substantially by Gerald Van Baren, Custom IDEAS, 24 * vanbaren@cideas.com. It was heavily influenced by LiMon, written by 25 * Neil Russell. 26 */ 27 28 #include <common.h> 29 #ifdef CONFIG_MPC8260 /* only valid for MPC8260 */ 30 #include <ioports.h> 31 #include <asm/io.h> 32 #endif 33 #if defined(CONFIG_AT91FAMILY) 34 #include <asm/io.h> 35 #include <asm/arch/hardware.h> 36 #include <asm/arch/at91_pio.h> 37 #ifdef CONFIG_AT91_LEGACY 38 #include <asm/arch/gpio.h> 39 #endif 40 #endif 41 #ifdef CONFIG_IXP425 /* only valid for IXP425 */ 42 #include <asm/arch/ixp425.h> 43 #endif 44 #ifdef CONFIG_LPC2292 45 #include <asm/arch/hardware.h> 46 #endif 47 #if defined(CONFIG_MPC852T) || defined(CONFIG_MPC866) 48 #include <asm/io.h> 49 #endif 50 #include <i2c.h> 51 52 #if defined(CONFIG_SOFT_I2C_GPIO_SCL) 53 # include <asm/gpio.h> 54 55 # ifndef I2C_GPIO_SYNC 56 # define I2C_GPIO_SYNC 57 # endif 58 59 # ifndef I2C_INIT 60 # define I2C_INIT \ 61 do { \ 62 gpio_request(CONFIG_SOFT_I2C_GPIO_SCL, "soft_i2c"); \ 63 gpio_request(CONFIG_SOFT_I2C_GPIO_SDA, "soft_i2c"); \ 64 } while (0) 65 # endif 66 67 # ifndef I2C_ACTIVE 68 # define I2C_ACTIVE do { } while (0) 69 # endif 70 71 # ifndef I2C_TRISTATE 72 # define I2C_TRISTATE do { } while (0) 73 # endif 74 75 # ifndef I2C_READ 76 # define I2C_READ gpio_get_value(CONFIG_SOFT_I2C_GPIO_SDA) 77 # endif 78 79 # ifndef I2C_SDA 80 # define I2C_SDA(bit) \ 81 do { \ 82 if (bit) \ 83 gpio_direction_input(CONFIG_SOFT_I2C_GPIO_SDA); \ 84 else \ 85 gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SDA, 0); \ 86 I2C_GPIO_SYNC; \ 87 } while (0) 88 # endif 89 90 # ifndef I2C_SCL 91 # define I2C_SCL(bit) \ 92 do { \ 93 gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SCL, bit); \ 94 I2C_GPIO_SYNC; \ 95 } while (0) 96 # endif 97 98 # ifndef I2C_DELAY 99 # define I2C_DELAY udelay(5) /* 1/4 I2C clock duration */ 100 # endif 101 102 #endif 103 104 /* #define DEBUG_I2C */ 105 106 #ifdef DEBUG_I2C 107 DECLARE_GLOBAL_DATA_PTR; 108 #endif 109 110 /*----------------------------------------------------------------------- 111 * Definitions 112 */ 113 114 #define RETRIES 0 115 116 #define I2C_ACK 0 /* PD_SDA level to ack a byte */ 117 #define I2C_NOACK 1 /* PD_SDA level to noack a byte */ 118 119 120 #ifdef DEBUG_I2C 121 #define PRINTD(fmt,args...) do { \ 122 printf (fmt ,##args); \ 123 } while (0) 124 #else 125 #define PRINTD(fmt,args...) 126 #endif 127 128 #if defined(CONFIG_I2C_MULTI_BUS) 129 static unsigned int i2c_bus_num __attribute__ ((section (".data"))) = 0; 130 #endif /* CONFIG_I2C_MULTI_BUS */ 131 132 /*----------------------------------------------------------------------- 133 * Local functions 134 */ 135 #if !defined(CONFIG_SYS_I2C_INIT_BOARD) 136 static void send_reset (void); 137 #endif 138 static void send_start (void); 139 static void send_stop (void); 140 static void send_ack (int); 141 static int write_byte (uchar byte); 142 static uchar read_byte (int); 143 144 #if !defined(CONFIG_SYS_I2C_INIT_BOARD) 145 /*----------------------------------------------------------------------- 146 * Send a reset sequence consisting of 9 clocks with the data signal high 147 * to clock any confused device back into an idle state. Also send a 148 * <stop> at the end of the sequence for belts & suspenders. 149 */ 150 static void send_reset(void) 151 { 152 I2C_SOFT_DECLARATIONS /* intentional without ';' */ 153 int j; 154 155 I2C_SCL(1); 156 I2C_SDA(1); 157 #ifdef I2C_INIT 158 I2C_INIT; 159 #endif 160 I2C_TRISTATE; 161 for(j = 0; j < 9; j++) { 162 I2C_SCL(0); 163 I2C_DELAY; 164 I2C_DELAY; 165 I2C_SCL(1); 166 I2C_DELAY; 167 I2C_DELAY; 168 } 169 send_stop(); 170 I2C_TRISTATE; 171 } 172 #endif 173 174 /*----------------------------------------------------------------------- 175 * START: High -> Low on SDA while SCL is High 176 */ 177 static void send_start(void) 178 { 179 I2C_SOFT_DECLARATIONS /* intentional without ';' */ 180 181 I2C_DELAY; 182 I2C_SDA(1); 183 I2C_ACTIVE; 184 I2C_DELAY; 185 I2C_SCL(1); 186 I2C_DELAY; 187 I2C_SDA(0); 188 I2C_DELAY; 189 } 190 191 /*----------------------------------------------------------------------- 192 * STOP: Low -> High on SDA while SCL is High 193 */ 194 static void send_stop(void) 195 { 196 I2C_SOFT_DECLARATIONS /* intentional without ';' */ 197 198 I2C_SCL(0); 199 I2C_DELAY; 200 I2C_SDA(0); 201 I2C_ACTIVE; 202 I2C_DELAY; 203 I2C_SCL(1); 204 I2C_DELAY; 205 I2C_SDA(1); 206 I2C_DELAY; 207 I2C_TRISTATE; 208 } 209 210 /*----------------------------------------------------------------------- 211 * ack should be I2C_ACK or I2C_NOACK 212 */ 213 static void send_ack(int ack) 214 { 215 I2C_SOFT_DECLARATIONS /* intentional without ';' */ 216 217 I2C_SCL(0); 218 I2C_DELAY; 219 I2C_ACTIVE; 220 I2C_SDA(ack); 221 I2C_DELAY; 222 I2C_SCL(1); 223 I2C_DELAY; 224 I2C_DELAY; 225 I2C_SCL(0); 226 I2C_DELAY; 227 } 228 229 /*----------------------------------------------------------------------- 230 * Send 8 bits and look for an acknowledgement. 231 */ 232 static int write_byte(uchar data) 233 { 234 I2C_SOFT_DECLARATIONS /* intentional without ';' */ 235 int j; 236 int nack; 237 238 I2C_ACTIVE; 239 for(j = 0; j < 8; j++) { 240 I2C_SCL(0); 241 I2C_DELAY; 242 I2C_SDA(data & 0x80); 243 I2C_DELAY; 244 I2C_SCL(1); 245 I2C_DELAY; 246 I2C_DELAY; 247 248 data <<= 1; 249 } 250 251 /* 252 * Look for an <ACK>(negative logic) and return it. 253 */ 254 I2C_SCL(0); 255 I2C_DELAY; 256 I2C_SDA(1); 257 I2C_TRISTATE; 258 I2C_DELAY; 259 I2C_SCL(1); 260 I2C_DELAY; 261 I2C_DELAY; 262 nack = I2C_READ; 263 I2C_SCL(0); 264 I2C_DELAY; 265 I2C_ACTIVE; 266 267 return(nack); /* not a nack is an ack */ 268 } 269 270 #if defined(CONFIG_I2C_MULTI_BUS) 271 /* 272 * Functions for multiple I2C bus handling 273 */ 274 unsigned int i2c_get_bus_num(void) 275 { 276 return i2c_bus_num; 277 } 278 279 int i2c_set_bus_num(unsigned int bus) 280 { 281 #if defined(CONFIG_I2C_MUX) 282 if (bus < CONFIG_SYS_MAX_I2C_BUS) { 283 i2c_bus_num = bus; 284 } else { 285 int ret; 286 287 ret = i2x_mux_select_mux(bus); 288 i2c_init_board(); 289 if (ret == 0) 290 i2c_bus_num = bus; 291 else 292 return ret; 293 } 294 #else 295 if (bus >= CONFIG_SYS_MAX_I2C_BUS) 296 return -1; 297 i2c_bus_num = bus; 298 #endif 299 return 0; 300 } 301 #endif 302 303 /*----------------------------------------------------------------------- 304 * if ack == I2C_ACK, ACK the byte so can continue reading, else 305 * send I2C_NOACK to end the read. 306 */ 307 static uchar read_byte(int ack) 308 { 309 I2C_SOFT_DECLARATIONS /* intentional without ';' */ 310 int data; 311 int j; 312 313 /* 314 * Read 8 bits, MSB first. 315 */ 316 I2C_TRISTATE; 317 I2C_SDA(1); 318 data = 0; 319 for(j = 0; j < 8; j++) { 320 I2C_SCL(0); 321 I2C_DELAY; 322 I2C_SCL(1); 323 I2C_DELAY; 324 data <<= 1; 325 data |= I2C_READ; 326 I2C_DELAY; 327 } 328 send_ack(ack); 329 330 return(data); 331 } 332 333 /*=====================================================================*/ 334 /* Public Functions */ 335 /*=====================================================================*/ 336 337 /*----------------------------------------------------------------------- 338 * Initialization 339 */ 340 void i2c_init (int speed, int slaveaddr) 341 { 342 #if defined(CONFIG_SYS_I2C_INIT_BOARD) 343 /* call board specific i2c bus reset routine before accessing the */ 344 /* environment, which might be in a chip on that bus. For details */ 345 /* about this problem see doc/I2C_Edge_Conditions. */ 346 i2c_init_board(); 347 #else 348 /* 349 * WARNING: Do NOT save speed in a static variable: if the 350 * I2C routines are called before RAM is initialized (to read 351 * the DIMM SPD, for instance), RAM won't be usable and your 352 * system will crash. 353 */ 354 send_reset (); 355 #endif 356 } 357 358 /*----------------------------------------------------------------------- 359 * Probe to see if a chip is present. Also good for checking for the 360 * completion of EEPROM writes since the chip stops responding until 361 * the write completes (typically 10mSec). 362 */ 363 int i2c_probe(uchar addr) 364 { 365 int rc; 366 367 /* 368 * perform 1 byte write transaction with just address byte 369 * (fake write) 370 */ 371 send_start(); 372 rc = write_byte ((addr << 1) | 0); 373 send_stop(); 374 375 return (rc ? 1 : 0); 376 } 377 378 /*----------------------------------------------------------------------- 379 * Read bytes 380 */ 381 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len) 382 { 383 int shift; 384 PRINTD("i2c_read: chip %02X addr %02X alen %d buffer %p len %d\n", 385 chip, addr, alen, buffer, len); 386 387 #ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW 388 /* 389 * EEPROM chips that implement "address overflow" are ones 390 * like Catalyst 24WC04/08/16 which has 9/10/11 bits of 391 * address and the extra bits end up in the "chip address" 392 * bit slots. This makes a 24WC08 (1Kbyte) chip look like 393 * four 256 byte chips. 394 * 395 * Note that we consider the length of the address field to 396 * still be one byte because the extra address bits are 397 * hidden in the chip address. 398 */ 399 chip |= ((addr >> (alen * 8)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW); 400 401 PRINTD("i2c_read: fix addr_overflow: chip %02X addr %02X\n", 402 chip, addr); 403 #endif 404 405 /* 406 * Do the addressing portion of a write cycle to set the 407 * chip's address pointer. If the address length is zero, 408 * don't do the normal write cycle to set the address pointer, 409 * there is no address pointer in this chip. 410 */ 411 send_start(); 412 if(alen > 0) { 413 if(write_byte(chip << 1)) { /* write cycle */ 414 send_stop(); 415 PRINTD("i2c_read, no chip responded %02X\n", chip); 416 return(1); 417 } 418 shift = (alen-1) * 8; 419 while(alen-- > 0) { 420 if(write_byte(addr >> shift)) { 421 PRINTD("i2c_read, address not <ACK>ed\n"); 422 return(1); 423 } 424 shift -= 8; 425 } 426 427 /* Some I2C chips need a stop/start sequence here, 428 * other chips don't work with a full stop and need 429 * only a start. Default behaviour is to send the 430 * stop/start sequence. 431 */ 432 #ifdef CONFIG_SOFT_I2C_READ_REPEATED_START 433 send_start(); 434 #else 435 send_stop(); 436 send_start(); 437 #endif 438 } 439 /* 440 * Send the chip address again, this time for a read cycle. 441 * Then read the data. On the last byte, we do a NACK instead 442 * of an ACK(len == 0) to terminate the read. 443 */ 444 write_byte((chip << 1) | 1); /* read cycle */ 445 while(len-- > 0) { 446 *buffer++ = read_byte(len == 0); 447 } 448 send_stop(); 449 return(0); 450 } 451 452 /*----------------------------------------------------------------------- 453 * Write bytes 454 */ 455 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len) 456 { 457 int shift, failures = 0; 458 459 PRINTD("i2c_write: chip %02X addr %02X alen %d buffer %p len %d\n", 460 chip, addr, alen, buffer, len); 461 462 send_start(); 463 if(write_byte(chip << 1)) { /* write cycle */ 464 send_stop(); 465 PRINTD("i2c_write, no chip responded %02X\n", chip); 466 return(1); 467 } 468 shift = (alen-1) * 8; 469 while(alen-- > 0) { 470 if(write_byte(addr >> shift)) { 471 PRINTD("i2c_write, address not <ACK>ed\n"); 472 return(1); 473 } 474 shift -= 8; 475 } 476 477 while(len-- > 0) { 478 if(write_byte(*buffer++)) { 479 failures++; 480 } 481 } 482 send_stop(); 483 return(failures); 484 } 485